This smoothie is a little tart because of the lemon and lime, but it’s well worth trying. The grapes and banana help to sweeten it a little. This smoothie might be small, but it’s loaded with nutrients. Just one cup of kale adds 8 percent of your recommended daily value of calcium, 10 percent of your recommended daily value of fiber, and 3 grams of protein. Most of the nutrients in the smoothie come from the kale.